When you add an user to a group in your directory service (bound to scm-manager through the ldap-plugin) it won't let users access the repository until you make some changes to permissions and/or groups.
- Create repository
- Add write permission for group from Active Directory to the repository
- Access repo by using a member of the AD-group and do something (works)
- Add another user to the AD-group
- Try to access the repository with the newly added AD-user (won't work)
- Create a new group in SCM-Manager and save it
- Access the repository with the user from steps 4/5 (will work)
It doesn't matter how long you wait between 2 access attempts except there is a server restart or a permission change between the 2 attempts. It's the same with removing a user from an active directory group.